Rotary gear pump



July 3, 1923.

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July 3, 1923. f 1,460,875

` A. WHITE V ROTARY GEAR PUMP Filed Sept. 27. 1921 5 Sheets-Sheet 5 l /4 /5 la 6] 70 6 y v F1515 my s, 1923.

A. WHITE ROTARY GEAR PUMP Filed Sept, 27 1921 5 Sheets-Sheet 4 v my 3, 191.23.

Filed sept. 27. 1921 1,460,875 A. WHITE ROTARY GEAR PUMP 5 Sheets-Sheet 5 Y 18 l 4l a A *"lm 3s f .4 ggg 16 Patented July 3, 1923.

UNITED STATES PATENT OFFICE.

ALPHONZO WHITE, OE WINCHENDON, HASSACHUBETTS, ASSIGNOB TO BAXTER D. WHITNEY 80N, INC., OF WINCHENDON, MASSACHUSETTS, A CORPORATION 0F MASSACHUSETTS.

ROTARY GEAR PUMP.

Application led September 27, 1981. Serial No. 503,554.

To all whom it may come/m:

Be it known thatI I, ALPHoNzo WHITE, a citizen of the United States, residin at Winchendon, county of Worcester, and tate of Massachusetts, have invented an AImprovement in Rotary Gear Pumps, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

This invention relates to a rotary gear pump, and more particularly to means for varymg the capacit of the pump.

It is often desira le to vary the amount of liquid delivered by a rotary gear pump without changing the speed at which the pump is operated. It has been proposed heretofore to provide an adjustable relief valve to permit liquid to escape through the valve as the pressure of the liquid in the pump exceeds the maximum for which the valve is set. This construction for permitting the excess liquid to escape wastes power since more liquid is pumped into the high pressure part of the pump than is needed, and is unsatisfactory in other respects.

It has been customary heretofore to vary the amount of liquid delivered by a pumpV by varying the speed at which the pump is operated, but this necessitates the use of gear-reducing mechanism, or other more or less complicated mechanism for operating the pump at different speed.

An important feature of the present invention, therefore, consists in valve means for controlling the passage of liquid from the different gears of a rotary pump to the high pressure chamber ofthe pump, and in means for permitting the liquid to escape from the high pressure side of the rotary gears without entering the high pressure chamber of the pump.

Another important feature ofthe invention consists in valve controlled means for by-passing the liquid from the high pressure side of the rotary gears, back to the low pressure side of said gears without'entering the high pressure chamber of the pump.

The above and other features of the invention and novel combinations of parts will be herein described in connection with the accompanying drawings which show one good, practical form of the invention.

In the drawings Figure 1 is a perspective view of a portlon of a rotary gear pump embodying the mventlon; l

Fig. 2 is a face view of Fig. 1, showing the gears in place;

Fig. 3 is a side view of the pump;

Fig. 4 is an end view showing the high pressure end of the pump;

Fig. 5 is a sectional view taken on line 5-5 of Fig. 4;

Fig. 6 ,1is a sectional view taken on line 6 6, Fig. 3;

Fig. 7 is a sectional view taken on line 7-7 of Fig. 3;

Fig. 8 is a sectional view taken on line 8-8 of Fig. 3.

Fig. 9 is a sectional view taken on line 9-9 of Fig. 4; and

Fig. 1()y is a sectional view taken on line 10--10 of Fig. 4.

In the embodiment of the invention shown in the drawings, the pump casing consists of a low pressure casing 10 and a high pressure casing 11 having ange portions 12 and 13 respectively, clamped to the opposite faces of the face plate 14 by bolts 15. Within the casing 10 is formed the low pressure chamber 16 havingan inlet opening 17 (see Fig. 7) through which liquid is admitted to the chamber 16 from a tank or other suitable source of supply (not shown). The high pressure casing 11 has a high pressure chamber 18 and an outlet 19 leading from the chamber and through which the pump discharges.

Within the .pump casing may be mounted any preferred number of gears, and the gears may be given any suitable arrangement for forcing the liquid fromthe low pessure chamber to the high pressure chamr. illustrated, the face plate 14 has gear-receiving pockets 20 formed therein, three beingl shown in the present instance, and a gear 21 is mounted in each pocket. The gears 21 are rotatably supported by the stud shafts 22 preferably secured to the gears by keys 23, and the opposite ends of the stud shafts are rotatably mounted in sockets 24 and 25 formed in the casings 10 and 11,respectively. The gears 21, in the present instance, are driven by a central gear 26 mounted `within In the embodiment of the inventiona space 27 formed within the face plate 14, and the gear 26 is keyed to a shaft 28 journaled in bearings 29 and 30 formed in the casings 10 and 11 respectively. One end of the-shaft 28. extends through the pump casing to be driven from any suitable means (not shown), and the shaft preferably extends outwardly from the low pressure side of the pump casing, rather than from the high pressure side of the casing to lessen the tendency of the liquid to4 leak around the shaft. Leakage about the shaft 28 may be prevented by a suitable stuffing-box 31.

In the present case communication between t-he low pressure chamber 16 and the gears 21 is provided by ports 32, (seeJ Fig. l) and communication between the gears 21 and the high pressure chamber 18 1s provided by the ports 33, one of which is shown in Fig. 8 while the other two are partially hidden in this View by the valves 41, to be described. It is desirable that a clearance space for the liquid be provided upon each sideof t-he points where the gears 21 mesh with the driving gear 26, and to this end, the face plate 14 is cut-away as at 34.

If the gears are driven rapidly there 1s a tendency to trap the liquid between a groove of one gear and a tooth of another gear as a tooth enters a groove. This is objectionable as it tends to retard the rotation of the gears, and also to force them apart; and to prevent this, in the present instance, the bottoms of the grooves of the gears are cut-away at an inclined angle as at and 36, to facilitate escape of the liquid from between two teeth toward the high pressure chamber as will be apparent from Fi 6.

is stated, an important feature of the present invention consists in valve-controlled means for selectively by-passing the liquid from the high pressure side of the rotary gears so that it may escape from the gears without entering the high pressure chamber, and satisfactory means to this end will now be described.

Should it be desirable to operate a rotary gear pump having a plurality of gears, at less than its full capacity, without reducing the speed at which the pump is driven, this may be accomplished in accordance with the present invention by by-passing the liquid from the high pressure side of one or more gears, back tothe low pressure chamber without being subjected to the pressure of the high pressure chamber so that less than all the pumping gears will deliver liquid to the high pressure chamber of the pump. In the present instance this is accomplished by providing one or more of the ports 33 with one conduit 37 leading to the high pressure chamber 18, and a second conduit 38 leading to a chamber 39 which, in the present instance, communicates with the low pressure chamber 16 through a conduit 40.. The communications between the port 33 and the conduits 37 and 38 are controlled by a valve 41 adjustable to one position to establish communication between the port 33 and high pressure chamber 18, and adjustable to a second position to close this communication and establish a communication between the ort 33 and the chamber 39.

. pon referring to Fig. 8 it will be seen that the high pressure chamber'18 and the small low pressure chamber 39 are formed in the high pressurecasing 11, while the larger low pressure chamber 16 is formed in the low pressure casing 10, and by referring to Fig. 9 it will be seen that li uid in the chamber 39 passes freely to the ow pressure chamber 16 through the conduit 40.

In the embodiment of the invention illustrated, two of the three ports 33 are provided with the adjustable valves 41 and means for by-passing the liquid, and the ar rangement 1s such that if it is desired to operate the pump at full capacity, both valves 41 will be adjusted to deliver liquid to the high pressure chamber 18; but if it is desired to operate the pum at less than full capacity, one, or if desire both valves 4l may be adjusted to discharge the liquid from their respective gears into the low pressure chamber 39. It will be apparent that, due to this construction the liquid from one or more gears may be returned freely to the low pressure chamber without being subjected to the ressure of the high pressure chamber, and t e power required to operate the pump will decrease as one or both of the valves 41 are adjusted to discharge the liquid into the low pressure chamber 39. From the foregoing it will be seen that one port 33 remains at all times in direct communication with the high pressure chamber 18 while the other two ports 33 will discharge liquid either into the high pressure chamber 18 or the small low pressure chamber 39 depending upon the adjustment of the valves 41.

The valves 41 may be adjusted by rotating the valve stems 42 extendingoutwardly through stuiiing-boxes 43 upon the rear face of the pump, and the position to which the valves are. adjusted may be indicated by providing a line or the like 44 upon the end of the valve stem 42, which may be adjusted relatively to arrows or other marks 45 upon the bosses 46 It is desirable to provide means for preventing the pressure in the high pressure chamber from becoming too great, and to this end an adjustable relief valve may be provided for permit-ting liquid to escape from the high pressure chamber. In the present instance this is accomplished by Vproviding a ball valve 47 cooperating with a valve seat 48 located at one end of a port 49 leadin from the high pressure chamber 18 to theIower ressure chamber 16. The ball valve 47 is oosely seated in a socket 50 formed in a head 51 u on the inner end of a sliding stem 52. T e stem 52 is urged toward the valve seating position by a spring 53 confined between the head 51 and the inner end of an adjustable sleeve 54. The tension of the spring may be varied by rotating the sleeve 54 within the threads 55 of the casing, and a handwheel 56 serves'to rotate the sleeve and also to coo erate with a scale 57 that indicates the adjustment of the sleeve. The arrangement is such that the maximum pressure within the high pressure chamber will depend upon the adjustment of the handwheel 56 to tension the spring 53.

It is desirable to provide means for holding the casings 10 and 11 and the face plate 14 in alignment while the bolts 15 are being inserted through the flange 13, the holes 58 in the face plate 14, and into threaded engagement with the ange 12, and to this end a uide pin 59 may be rovided as shown ingFig. 2. The outer en of the high pres'- sure chamber 18 is shown as closed by a cover plate 6() which is secured in place by bolts 61, and the stulling boxes 43 are mounted in this cover plate.

The present invention provides an eX- tremely simple and satisfactory means for varying the amount of liquid that will be delivered to the high pressure side of the pump, since without chan ing the speed at which the pump is opera the capacity of the pump may be reduced one-third by opening one valve 41, and may be reduced another third by opening the second valve 41. And should a greater ran in the capacity of a pump be desired, 1t may be obtained by providing a pump with a greater number of pumping ears and cooperating valves than are s ownin the present casing.

The pump forming the subject matter of the present invention is well adapted for various purposes, and is particularly well adapted for use in connection with the hydraulically-operated wood `cutting machine shown and described in the co-pendin application Serial Number 498,811, filed September 6, 1921, in which application the present pump is shown as comprising the means for supplying the hydraulic operating fluid to the hydraulic means at the desired velocity and pressure.

What is claimed is 1. In a rotary gear pump, in combination, a casin having a high pressure chamber, a plura iteof gears for forcing liquid into said cham r, means for supplying liquid to the gears, means for rotating said gears, communications between said gears and the high pressure chamber and between the high pressure side of said gears and the means or supplying liquid to the gears, and valves adjustable to one position to admit liquid from the gears to the high pressure chamber and adjustable to a second position to close the communication between one or more of said ears and chamber and to bypass the liquiffrom said gear or gears back to the liquid supply means without entering the high pressure chamber.

2. In a rotary gear pump, in combination, a casing having a high pressure chamber, gears for forcing liquid into said chamber, means for supplying liquid to said gears, means for rotating said gears, communications between said gears and the high pressure chamber, and a valve in one of said communications adjustable to one position to direct the liquid from the gear to the high pressure chamber and adjustable toa second position to by-pass the liquid from the gear back to said liquid supply means without entering the high pressure chamber or being subjected to the .pressure thereof.

3. In a rotary gear pump, in combination, a casing having a high pressure chamber, a plurality of gears for forcing liquid into said chamber, means lfor supplying liquid to the low pressure side of said gears, means for rotating said gears, communications between the high pressure side of said gears and the high pressure chamber, and valves for selectively closing said communications and by-passing the liquid back to the liquid supply means so that the liquid may be returned to the liquid supply means without being subjected to the pressure of the high pressure chamber.

4. In a rotary gear pump, in combination, a casing having a high pressure chamber and a low pressure chamber, a plurality of gears for forcing liquid from the low pressure chamber to the high pressure chamber, communications between the gears and chambers, means for rotating the gears, and i valve means operable selectively to close one or more of the rcommunications between the gears and high pressure chamber .ind to by-pass the liquid back to the low pressure chamber so that the liquid may be returned to the low subjected to the sure chamber.

5. In a rotary gear pump, in combination, a casing having a high pressure chamber, a

pressure of the high presplurality of gears for forcing liquid into said chamber, means for supplying liquid to the low pressure side of said gears, means for rotating'said gears, communications between the high pressure chamber and the respective gears, an adjustable relief valve for controlling the maximum pressure in the high pressure chamber, and valves oppressure chamber without being' erable selectively to close one or more of said communications and by-pass the liquid back to the liquid supply means without being subjected to the pressure of the high pressure chamber.

6. In a rotary gear pump, in combination, a casing having a high pressure chamber and a low pressure chamber, a plurality of gears for forcing liquid from the low pressure chamber to the high pressure chamber, communications between the gears and chambers, means for rotating the gears, valve means operable selectively to close the communications between the gears and high pressure chamber and to by-pass the liquid back to the low pressure chamber without being subjected to the pressure of thehigh pressure chamber, and an adjustable relief valve for controlling the maximum pressure in the high pressure chamber.

7. In a rotary gear pump, in combination, a casing having a high pressure chamber and a low pressure chamber, a plurality of gears for forcing liquid from the low pressure chamber to the high pressure chamber, communications between the gears and chambers. communications between the high pressure side of the gears and the low pressure chamber, means for rotating the gears, and valves in said communications adjustable to one position to admit the liquid from the high pressure side of the gears to thel high pressure chamber and adjustable to a second posit-ion to by-pass the liquid back to the low pressure chamber without being subjected to the pressure of the high pressure chamber.

8` In a -rotary gear pump, in combination, a casing having a high pressure chamber and a low pressure chamber, gears for forcing liquid from the low pressure chamber to the high pressure chamber, means for rotating the gears, communications between the gears and chambers, a communication between the high pressure side of one of said gears and the low pressure chamber, and a valve adjustable to one position to by-pass the liquid from said gear back to the low pressure chamber without being` subjected to the pressure' maintained in the high pressure chamber by the other gear or gears and to another position to direct the liquid into the high pressure chamber.

9. In a rotary gear pump, in combination, a casing having a high pressure chamber, gears for forcing, liquid into said chamber, means for rotating said gears, means for supplying liquid to said gears, communications between the gears and high pressure chamber, and valve-controlled means for selectively ley-passing the liquid from the high pressure side of the gears so that the liquid may escape freely from the gears without entering the high pressure chamber or being subjected to the pressure thereof.

In testimony whereof, I have signed my name to this specification.

ALPHONZO WHITE. 

